In cases of possible mesothelioma, the first method of determining whether or not the patient has the disease is by means of non-invasive examination of his or her internal conditions through X-ray photography, CT scans, MRIs, and PET scans.
X-ray photography dates back to the 19th Century. It works by placing the patient between a source of X-rays and a piece of X-ray sensitive film. When exposed, the patient’s body is penetrated by these X-rays, which pass through the flesh and organs in the body, but are absorbed by thicker matter such as bones, tumors, etc.
The X-rays that pass through strike the film emulsion, turning it dark; those that are absorbed by internal structures do not pass through, leaving light spots on the film. The negative image that is thus produced shows what the body looks like inside.
- CT (Computerized tomography) scanning – the familiar “CAT scan” – also uses X-rays, this time focused in a single plane, producing a series of images in the form of thin, cross-sectional “slices” of the body. By examining these “slices”, radiologists can determine the location of internal organs and other objects, including malignancies.
- MRI (Magnetic Resonance Imaging) is similar to CT scanning, but does not use X-rays. Instead, a powerful magnetic field is used to cause the body’s water molecules to line up along a single axis. When these aligned water molecules are “tickled” into motion by a second magnetic field, they give off a distinctive burst of energy that the scanner detects and converts into an image. MRI scan images are more detailed and sharp than CT scan images.
- PET (Positron Emission Tomography) produces a sharp, clear 3-D image by means of antimatter. The patient is administered a harmless radioactive tracer liquid prior to the scan; this tracer flows through the body and becomes concentrated in its tissues. As the radioactive atoms in the liquid decay, they each emit two 511 keV gamma rays (powerful beams of radiation) that are detected by the PET scanner. Since these gamma rays are emitted in opposite directions, the scanner can also compute the precise location within the body whence they originated, allowing the machine to produce a 3-D picture of the patient’s interior.
When searching for evidence of mesothelioma, X-rays and other forms of non-invasive examination are vital. If the patient has internal tumors or other evidence of mesothelioma, CAT scans, MRIs, and PET scans can literally show these, allowing the doctor to make a reliable diagnosis.
